Difference Between Class and Object in Java

Introduction

In Java and other object-oriented programming languages, classes and objects are the foundational building blocks. Understanding the difference between a class and an object is essential for writing efficient and maintainable code.

In this article, we’ll cover:

• What is a class?

• What is an object?

• Key differences between class and object

• Real-world examples

• Code snippets

 What is a Class in Java?

A class is a blueprint or template for creating objects. It defines variables (fields) and methods (functions) that describe the behavior and properties of an object.

Syntax Example:

class Car {
    String model;
    int year;

    void drive() {
        System.out.println("Car is driving");
    }
}

Here, Car is a class that defines what a car has and does.

What is an Object in Java?

An object is an instance of a class. When a class is instantiated using the new keyword, it becomes an object.

Object Example:

public class Main {
    public static void main(String[] args) {
        Car myCar = new Car(); // Object creation
        myCar.model = "Toyota";
        myCar.year = 2020;
        myCar.drive();
    }
}

Here, myCar is an object of the Car class.

Difference Between Class and Object

Real-Life Analogy

Think of a class as an architectural blueprint of a house.

• The blueprint itself is not a house.

• But using the blueprint, you can build multiple objects (houses).

So:

• Class = Blueprint

• Object = Actual house built from blueprint

Key Points

• You can create multiple objects from a single class.

• Changes in one object do not affect others.

• A class defines what an object should be.

FAQs

Q1: Can we create an object without a class?
No. Every object in Java must be created from a class.

Q2: Can we define a method in an object directly?
No. Methods are defined in a class, and called through objects.

Q3: Are class and object both mandatory in Java?
Yes. Java is a purely object-oriented language. You need both.

Related Articles

• Introduction to Java Classes

• Constructors in Java

• OOPs Concepts in Java